Scientists from Northumbria University and Southamton University in England and BASF in Norway reported that while 26 weeks of supplementation with a DHA-rich fish oil did not produce improvements in those end-points compared to placebo, the DHA-rich supplement did improve reaction time, compared to placebo.
“To our knowledge, the current trial is the first to investigate and identify significant improvements in healthy young adults in both global accuracy and speed of cognitive function following supplementation with EPA-enriched oil compared with placebo,” wrote the researchers in the American Journal of Clinical Nutrition.
BASF AS funded the study and supplied all the capsules used.
“An important new study”
Commenting independently on the study, William Harris, PhD, President and Founder of the Fatty Acid Research Institute (FARI), told NutraIngredients-USA. “This is an important new study that contributes significantly to the understanding of the role that omega-3 fatty acids may play in preserving mental health.
“It’s important for three reasons: 1) it was done in healthy young adults, not the aged or infants; 2) it used only about 1200 mg of EPA+DHA and did so for only 6 months; and 3) it found that EPA-rich (not pure) oils were more effective than DHA-rich (not pure) oils in affecting cognitive function.
“These observations will help future researchers refine and deepen this line of investigation.”
Study details
The researchers recruited 310 healthy adults aged between 25 and 49 to participate in their randomized controlled trial. Volunteers were randomly assigned to one of three groups: The first group received DHA-rich fish oil supplements (900 mg DHA/d and 270 mg EPA/d); the second group received EPA-rich fish oil supplements (360 mg DHA/d and 900 mg EPA/d); and the third group received 3 grams per day of olive oil (placebo).
A series of memory asks were performed at the start of the study and again after 26 weeks. Prefrontal cortex (PFC) hemoglobin (Hb) oxygenation was also measured using near-infrared spectroscopy (NIRS).
The results indicated that participants consuming the EPA-rich fish oil performed significantly better than placebo for global accuracy scores, better than placebo and DHA for global accuracy, and better than DHA for accuracy of memory scores.
While the EPA-rich supplement did not lead to significant improvements in reaction times, compared to placebo, statistically significant improvements in reaction time were recorded for the DHA group during the learning phase of the overnight memory consolidation tasks, compared to placebo.
There was a trend for reduced PFC oxygenated Hb in both fish oil groups, but these measures did not reach statistical significance, said the researchers.
The scientists said the results extend previous finding from older adults and together this data suggest that, “although EPA is stored in the brain in low amounts, it may still play an important role in higher-order cognitive functions, as has been suggested previously.
“In contrast, and somewhat surprisingly, these beneficial effects were not seen following the DHA-rich oil, where improvements to cognition were limited to improved word recognition RTs during the learning phase of the overnight memory consolidation tasks,” they noted.
“These results indicate that supplementation with EPA over DHA may be more beneficial in healthy young adults in terms of cognitive outcomes. It also demonstrates that the ratio of EPA and DHA in the investigational treatments provided to participants could be an important consideration that can greatly influence study outcomes.
“Given the emphasis on DHA in the literature to date, if supplementation with DHA is indeed less relevant in healthy young populations, this may in part explain the limited effects that have been reported previously,” they added.
Source: The American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1093/ajcn/nqab174
“Supplementation with oil rich in eicosapentaenoic acid, but not in docosahexaenoic acid, improves global cognitive function in healthy, young adults: results from randomized controlled trials”
Authors: M.J. Patan, et al.